I got a question for you: Early diastole is a suction mechanism between the atrial and ventricular chambers. Then, in late ventricular diastole, the two atrial chambers contract (atrial systole), causing blood pressure in both atria to increase and forcing additional blood flow into the ventricles. This beginning of the atrial systole is known as the atrial kick -- see Wiggers diagram. The atrial kick does not supply the larger amount of flow (during the cardiac cycle) as about 80 per cent of the collected blood volume flows into the ventricles during the active suction period.

Based on this passage, about 80 of blood is passed from the atria to ventricles by?
Let's think first:
The relevant sentence in the passage is: The atrial kick does not supply the larger amount of flow (during the cardiac cycle) as about 80 per cent of the collected blood volume flows into the ventricles during the active suction period.
Therefore, the answer is the active suction period.